A main difficulty associated with this recent diversification of wing
character suites is lack of downward compatibility. The morphometric definition
of the currently recognized Apis mellifera subspecies has been based on
traditional classical morphometry; consequently, studies based on a geometric
character set cannot utilize reference data generated with traditional wing
angle measurements accumulated in previous work by various authors, including
the reference subspecies descriptions as given in Ruttner’s (1988) monograph.

Fortunately, however, there is a high degree of consensus concerning the
marking points between the different kinds of wing shape analysis. Fig. 2 shows
the 20 landmarks predominantly used in geometric morphometry. Tofilski (2004,
2008) omitted landmark 15, while Kandemir
et al. (2011), following Zelditch et al.
(2004), moved point 15 from the apex of the radial cell to the junction of Rs5
and the costa, and located one additional point at the end of the vannal fold.
Classical morphometry and the DAWINO method use the same landmarks, omitting
point 15. However, the methods disagree in the sequence of numbering these
points, which is of no major concern.

To overcome the present sets of incompatible data and to avoid further
parallel development of incompatible data sets in honey bee morphometry, our
suggestion for a standardization of wing measurements is to store all future
data as point coordinates (instead of the format of derived characters such as
angles) to facilitate data exchange between different studies and research
teams. We suggest using the point format exemplified in the description of
Apiclass (http://apiclass.mnhn.fr), shown in Fig. 2. From these coordinates, used in a
majority of geometric studies, all 30 DAWINO characters can be calculated,
which include the Ruttner (1988) wing angles as a subset. Storing the point
coordinates instead of calculated characters will also keep all options open
for any future progress in analysis techniques. Unfortunately, however, the
coordinates cannot be recreated from classical wing angles, but first attempts
have been made to re-measure reference samples with the geometric method
(Kandemir et al., 2011) to link geometric morphometry to subspecies
characterizations obtained by the classical method.

As a
further issue the question arises whether geometric morphometry should replace
"classical" morphometry for good, meaning that the accurate, powerful
and labour-effective shape analysis based on wing geometry alone should replace
the full set of classical characters, including all traditional body
characters. Phylogenetically, the wing venation is more informative compared to
the more environment–sensitive character categories of size, colour or pilosity
(Diniz Filho et al., 2000), and thus represents a character set somewhat
comparable to molecular characters. A high degree of consistency between wing
morphometry and molecular information has been demonstrated by Miguel et al.
(2010). Therefore, wing geometry is particularly suitable to track phylogenetic
relationships between subspecies, where the full "classical"
character set can be misleading. However, aiming at an inventory of honey bee
variation as a numerical account of ecotype morphology, it appears
indispensable to maintain classical morphology with a broad character set to
represent the actual features of subspecies or ecotypes, apart from and in
addition to the question of their phylogeny. However, geometric wing venation
morphometry might replace the classical wing angles even within the classical
morphometry set, but no attempt has been made so far to combine these methods.